This invention relates generally to fiber optics and more particularly to a connector for coupling or splicing optical fibers end-to-end wherein the fibers are easily brought together for continuous light transmission.
Various connectors have been proposed for coupling optical fibers end-to-end. These connectors either have been of a permanent nature forming a splice between the optical fibers; or they have been of a mechanical nature employing male and female coupling components providing a disconnectable butt connection. These connectors have often required the use of precision micromanipulators or microscopes to affect the connection since the diameter of an optical fiber is usually in the range of 10 to 500 microns.
After considerable research and experimentation, the connector of the present invention has been devised which can be employed either as a permanent splice between the ends of aligned optical fibers or it can be employed as a disconnectable connector between the fiber ends. The connector of the present invention is constructed and arranged to be a low cost, low loss connector or splicer for use in the field and thus not requiring precise instruments to facilitate the connection or splice.
The connector of the present invention comprises, essentially, a graded index rod having a longitudinally extending bore extending along the longitudinal axis thereof. The ends of the optical fibers to be connected are inserted into opposite ends of the rod bore and positioned to a focal length until a maximum power output is detected at the required destination for which the connection is made. A suitable adhesive is provided for holding the ends of the optical fibers within the rod bore, whereby the connection can be made and disconnected many times, as desired. A permanent cement is employed when splicing the optical fibers together.
The graded index rod can be inserted within and secured to a sleeve having a threaded outer wall. A cap having an axially extending bore aligned with the rod bore is threaded on each end of the sleeve, and the fibers to be connected extend through a respective cap bore and into the rod bore. The optical fibers are adhesively connected to the caps, whereby adjustment of the fiber spacing to the desired focal length is accomplished by rotation of the end caps relative to the sleeve.